Abstract

X-ray structural analysis and high-temperature thermoelectric properties measurements are performed on polycrystalline samples of artificial mineral Cu12−xNixSb4S13 tetrahedrite. Analysis of the atomic displacement parameter manifests low-energy vibration of Cu(2) out of CuS3 triangle plane. The vibration results in low lattice thermal conductivity of less than 0.5 W K−1 m−1. By tuning of the Ni composition x and decrease of electronic thermal conductivity, dimensionless thermoelectric figure of merit for x = 1.5 achieves 0.7 at 665 K, which is a considerably high value among p-type Pb-free sulfides. Because the tetrahedrite is an environmentally friendly material, it constitutes a good thermoelectric material for use in support of a sustainable society.

Received 13 December 2012Accepted 08 January 2013Published online 28 January 2013

Acknowledgments:

This work was supported financially by a Grant-in-Aid for Research Activity Start-up (Grant No. 22840021) from JSPS, by a Grant-in-Aid for Young Scientists (B) (Grant No. 23760628) from MEXT, by a grant from the Thermal and Electric Energy Technology Foundation, and by a grant from the Japan-U.S. Cooperation on Clean Energy Technologies funded by METI, Japan. The synchrotron-radiation powder experiments were conducted at the SPring-8 BL02B2 beamline with the approval of JASRI (2012B1285).